Warren Zaire Emery initially put the home team ahead, but the visitors' Nahuel Molina quickly responded in the first half of what turned out to be a mostly lackluster match. However, Angel Correa sealed the deal for the visitors with a winning goal three minutes into stoppage time.
On four points from as many games, PSG are 25th in the 36-team league, six points behind fellow Ligue 1 teams Monaco and Stade Brestois, while Atleti moved out of the red zone with six points.
PSG next travel to Bayern Munich and RB Salzburg while Atletico play Sparta Prague away and Slovan Bratislava at home.
Hakimi shot just wide before Dembele’s effort whizzed over the bar as PSG made a lively start.
PSG, who have struggled in the competition this season, were gifted the opener when Clement Lenglet was easily dispossessed in the box by Dembele, who fed Zaire Emery and his France team mate finished with a clinical chip in the 14th minute.
That spurred Atleti into action and four minutes later Molina smashed a half volley home after poor defending by Nuno Mendes following Gianluigi Donnarumma’s initial save to deny Giuliano Simeone.
Dembele played chief tormentor early in the second half, bringing danger to the Atletico defence several times but it was Bradley Barcola who had the best scoring position, only to shoot straight at Jan Oblak.
Oblak palmed away another Barcola attempt in the 65th minute as PSG increased the pressure.